@Fetch load() from TCA reducer

[sillygoose]

Updating an older TCA application and switching to SharingGRDB from another database.so lots of new stuff to learn. Hopefully there is a simple answer to my question as I learn to use FetchAll, FetchOne, and Fetch, which I decided to use since I need implement a dynamic query. Here is what I have which works but I can't figure out to call the load() function.

    @Fetch(Trips(), animation: .default) var trips = Trips.Value()
    struct Trips: FetchKeyRequest {
      struct Value: Equatable {
        var trips: [Trip] = []
        var duration: Duration = .seconds(0)
        var distance: Measurement<UnitLength> = Measurement(value: 0, unit: UnitLength.kilometers)
        ...
      }

      func fetch(_ db: Database) throws -> Value {
      ...

From fetch() I have a dynamic query that selects the trips using a data range:

let tripsQuery =
        Trip
          .where {
            $0.timeStart >= startFromDate && $0.timeStart < endAtDate
          }
          .order { $0.timeStart.desc() }

Everything works fine except for the query updates when the display dates change, either from the TCA Reducer or from the View with a task similar to this:

Task { [state = state] in
          await withErrorReporting {
            try await state.$trips.load(Trips(), animation: .default)
          }
        }

The error I get is

Instance method 'load(_:database:animation:)' requires that 'Trips' conform to 'FetchKeyRequest'
Where 'some FetchKeyRequest<Value>' = 'Trips'

which has me stumped and looking for a little help. While I found examples like the DynamicQuery case study, none show doing this in TCA so any help is appreciated.

[mbrandonw]

Hi @sillygoose, could you create a quick, small repro of this problem so that we can take a look?

[sillygoose]

Added code to the TCA CaseStudies and got a different error that confirms I am an old fool:

Cannot find 'Trips' in scope

Back in my project I had the FetchKeyRequest structure in State

    @Fetch(Trips(), animation: .default) var trips = Trips.Value()
    struct Trips: FetchKeyRequest {
    ...

so the solution was to add State to the load():

    try await state.$trips.load(State.Trips(), animation: .default)

and it builds and works correctly.

So why the quirky error diagnostic? Guessing that the Swift compiler was confused by my TCA feature is also Trips:

@Reducer
struct Trips {

Sorry to bother you, I guess I'll treat myself to the new episode that just dropped.

[mbrandonw]

Ah yeah, that makes sense. Glad you figured it out!